Rick Santorum’s decision to urge Michigan Democrats to vote for him in Tuesday’s Republican primary was “a desperate measure by a desperate campaign,” winner Mitt Romney told Newsmax.TV just hours after his victory.

And although Santorum could adopt the same tactic in five open-primary states that vote next week on Super Tuesday, “Republicans are ultimately the ones who will decide who our nominee’s going to be,” Romney said during the exclusive interview.

“Desperate campaigns resort to desperate measures,” Romney said. “I am not going to worry too much about what the other guys are doing other than to point out when I think they are going against the kind of principles they have espoused in the past and that I think are right for our process.”

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He said Santorum said just a few weeks ago that primaries “ought to be contests where Republicans decide who a Republican nominee is.”

Santorum’s campaign “robocalled” Democrats in Michigan, asking them to turn out in the primary and vote for him. In the end Romney won his home state by 3 percentage points, but he said that would have been 10 points if it wasn’t for Democrats casting their ballot for the Pennsylvanian.

“To have a Republican pay money to contact Democrats and tell them to come in to a Republican primary and vote against me was something akin to what the Obama people are doing. I am not going to get in league with Barack Obama; that is a very bad course for this process,” said Romney.

The former Massachusetts governor said he accepted that members of all political stripes have the right to vote in open primary states. “It’s one thing for a citizen to make a decision on his own, it’s another thing for a presidential campaign to go out and do what he did.”

Romney said left-wing Michigan-born filmmaker Michael Moore even agreed with Santorum and was urging people to vote for the former senator. “If Democrats are telling people to vote for Rick Santorum, that ought to give Republicans something to think about.

Romney said he is running on his record as a conservative, which he described as “a heck of a lot stronger” than Santorum’s.

“As governor, balancing the budget all four years without raising taxes and without going out and borrowing more money, cutting taxes 19 times, having the state police enforce illegal immigration laws, having English immersion in our schools, and then standing up for life.

“I was a pro-life governor, I was a pro-traditional marriage governor, I was one of the nation’s leaders in favor of a national amendment to the Constitution defining marriage as a relationship between a man and a woman.

“My record as a conservative can be seen in my leadership in comparison with Senator Santorum. He voted against right-to-work laws; he voted to protect Davis-Bacon, which imposes union wages on government contracts; he voted to raise the debt ceiling five times without compensating cost cuts; he voted to fund Planned Parenthood; he voted for something he said that was against his principles, which was No Child Left Behind and said he did it because he was taking one for the team. This is not the kind of conservative leadership America’s looking for.”

Looking ahead, Romney said he has “a game plan” to win the GOP nomination and go on to face President Barack Obama in November’s election. He said he has not even “begun to think” about who his running mate would be if he is successful.

But he specifically mentioned businessman Donald Trump – whom his wife Ann thanked during his Michigan victory speech – along with Govs. Chris Christie of New Jersey and Bob McDonnell of Virginia and former candidate Tim Pawlenty as people who “have been remarkably helpful to my campaign.”